Railway traffic controlling apparatus



.My K6, 1940. M, R, sNYDER RAILWAY TRAFFIC CONTROLLING APPARATUS Filed May l5. 1939 GfH Y1 Pani-5b l l l I I 1 Patented July 16', 1940 Param ortiesy RAILWAY TRAFFIC CONTROLLING:`

. APPARATUS Mills Roger Snyder, Norfolk, Va., assigner to The v I Union Switch & Signal Company, Swissvale, *i*

Pa., a corporation of Pennsylvania Application May 16, 1939, Serial No. 273,974

8 Claims.

, My invention relates to railway traffic controlling apparatus. l

One object of my invention is to provide novel and improved means for operating arailway `l? vided if the switch were operated by a manually controlled power operated means.

l shall describe one form of apparatus embodying my invention, and shall then point out, the novel features thereof in claims.

20 The accompanying drawing is a diagrammatic View showing one form of apparatus embodying my invention forcausing the operation of `a railway switch when a car approaching theswitch passes over. a given track section in greater than a predetermined time' interval.

In the drawing in a number of. instances oneor more of the contacts of certain ones of the relays or devices are shown separated from the relays or devices themselves in order to enable the different circuits tobe more readily followed. Inl

each instance, each contact is given a reference character comprising a distinguishing number preceded by a dash and the reference character for the relay or device by which the contact is operated, and the contact is shown in the position corresponding to the normal condition of the relay or device. For examplathe reference characters GPS- I and GPS-2 applied to two of the contacts in the circuit for relay SWR indicate .that the associated contacts are the contacts I and 2 of relay GPS, and these contacts, being front contacts, are shown open since relay GPS is normally deenergized.

Referring to the drawing, a stretch of track X over which traflic normally moves in both directions is connected by means of a switch 3 with a diverging track Y which may, for example, comprise one end of a passing siding. `The main track X is provided with track sections IT, 4T, 5T, A5T, 6T, AST and 9T, while the diverging track Y is provided with a track section 3bT, the switch 3 being located in the track section 4T of the main track. For convenience, the section ABT will at times be referred to as an approach 5 section.

, 5- Each ktrack section is provided with a track circuit comprising the usual track relay R and a track battery. The track relays Ry are each indicated as associated withtheir respective track sections bytheir distinguishing preceding eX- 15. ponents.

The reference characters B and C designate the positive and negative terminals respectively` of a source of current not shown in the drawing.

The switch `3 is operated between its two eX- 10 treme positions by means of a switch machine SM which is responsive to the polarity of the current supplied thereto, and which is controlled by a polarized switch control relay SWR. The switch machine SM is preferably of. the well- 15 known dualcontrol electric type, and `may for example be similar to that described and claimed in an application for Letters Patent ofv the'United States, Serial No. 148,706, filed by William C. McWhirter and Edwin G. Little on January' 17, 20 1937, for Railway switch operating apparatus, now U. S. Letters Patent No. 2,183,164,`granted Dec. 12, 1939.

The circuits for controlling the switch machine by the switch control relay SWR `will be readily 25 understood from an inspection of the drawing, these circuits being so arranged that the switch machine will be deenergized, or will bey supplied with current of normal or reverse polarityy to move the switch to its normal or its reverse posi- 3,0 tion, according as the switch control relay is deenergized, or is energized by current ofl normal or reverse relative polarity. As is usual, when the switch machine becomes `oleenergized it will remain in the` position to which it was last moved 35 and will retain the switch lockedin this position. The switch machine SM includes a suitable circuit controller comprising pole changing contacts I0 and Ii, which contacts control the supply of current toa polarized indication relay KR in w such manner that the polar, relay will be energized by current of normal polarity when and only when the switch occupies its normal position and is properly locked in this position, and lby current of reverse polarity when and only when 45 the switch occupies its reverse position and is properly locked in this position. It follows, therefore, that whenever `the switch becomes unlocked or is in transit relay KR, will bedeenergized. i

The switch control relaySWR is controlledover a circuit which includesv front contacts GPS- I and GPS- 2 of a safety relay GPS, the front contacts I3 and I4 ofl track relay 4TH, and pole changing contacts SWS-I and 3WS--2` of. av 5v5 switch stick relay 3WS.` This circuit is so arranged that when relay GPS and track relay 4TR are both energized, the current supplied to relay SWR will have normal or reverse relative polarity according as relay SWS is then deenergized or energized, and it follows, therefore, that when relays GPS and 4TR are both energized the switch will be moved to its normal or its reverse position according as relay 3WS is deenergized or energized. relay SWS should become improperly deenergized for any reason, and the switch 3 does not already occupy its normal position, it will move to this position so that traflic can proceed along the main track past the switch without delay.

Traffic moving from left to right over stretch X, that is to say eastbound trailic, is governed by signals 3a, 5 and 9 located respectively at the entrance ends of sections 4T, 5T and 9T, while westbound traffic over this stretch is governed by signals 6 and 4a located respectively at the entrance ends of sections AST and 4T.4 Traffic leaving the siding Y is governed by a signal 3b, while traffic entering the siding isgoverned by a signal 4b. These signals may be of any preferred type, but as here shown they are color light signals, the signals 3a., 4a, 5, 6 and 9 each being provided with a green lamp G, a yellow lamp Y and a red lamp R, and the signals 3b and 4b each being provided with a yellow lamp Y and a red lamp R. The section A5T into which signal 5 governs the entrance of westbound traffic will preferably be so located with respect to the grade and curvature of the track as to allow the average trainy to maintain a speed in excess of a predetermined speed, for example, 30 miles per hour, for a predetermined distance past the signal, such for example as 550 feet. n

A fouling post FP is preferably located at the left-hand end of section SbT to indicate to an engineman the point at which he will start to tion indication when the distant relay SaD is deenergized and thehome relay 3aH is energized,

and the red lamp R will become lit to display a stop indication when the home relay is deenergized,

The signal 3111s controlled by a home relay Sol-I in such manner that the yellow or red lamp of this signal will be lighted to .display a vcaution or stopk aspect according as relay 3bH is energized or deenergized. The circuits for controlling this signal will also be obvious from an inspection of the drawing.

The signal 4b kis controlled by a home relay 4bH in the same manner that signal 3b is controlled by the relay Bbl-I. k

The signal la is controlled by a polarized home relay 4H and a slow releasing home repeater relay IflHP, the control circuits being so arranged that the green lamp G will be lighted when relay lll-IP is energized and relay 4H is energized'by 4current of normal polarity, the yellow lamp Y This arrangement insures that if ing circuits for thisv signal will be readily apparent from an inspection of the drawing.

The signal 5 is controlled by a polarized home relay 5H and a slow releasing homer repeater relay 5H? in the same manner that signal 4 is controlled by relays 4H and II-IP, and signal 6 is similarly controlled by relays 6H rand BHP.

The control relays and circuits controlled thereby for controlling signal 9 are not shown, but it will be readily understood that this latter signal is likewise controlled in a manner similar to signal 5.

The polarized relay 6H is controlled by track relays A5TR, 5TR and 4TH., and by a pole changing relay A4PC, over a circuit which includes a front contact l5 of track relay A5TR,La front contact I8 of track relay 5TR, a front contact 95 of track relay 4TR, and pole changing contacts Il and I8 of relay AAPC. This circuit is so only when relay 4H is energized by current of normal relative polarity.

Relay 4H is controlled over a polarized circuit which is similar to that just described for relay GH, only that portion of this circuit being shown which includes front contact I 2 of the track relay ITR. Inasmuch as the circuit for controlling relay 4H is similar to that for controlling relay BH, it is deemed to be unnecessary to describe it further herein.

The relay 6H controls the repeater relay BHP by virtue of a circuit which includes a front contact I8 of relay 6H, and it will be seen, therefore, that relay GHP will be energized Whenever relay 6H is energized.

Associated with signal 6 is the usual directional stick relay BS, which latter relay is controlled jointly by the track relay AST'R and home repeater relay 62E-IP in accordance with well-known practice in such manner that this relay will become picked up when a westbound train, enters section A5TR, and will subsequently be held in its picked up condition until the train which` caused it to pick up clears section 5T, but will remain deenergized during movement of an eastbound train over track X. The pick-up circuit for relay SS may be traced from terminal B through front contact 2li-20a of relay BHP, back Contact 2l of relay A5TR and the winding of relay GS to terminal C. This circuit will become closed only fork the brief interval of time required` for front contact 2li- 20d of relay BHP to openafter track relay A5'IRv becomes deenergized, it being obvious that the deenergiza` tion of track relay A5'I'Rideenergizes relay 6H and hence relay BHP. One stick circuit for relay GS passes from battery B through back contact 22 of track relay A5'IR,'front contact 23 of stick relay BS, and the winding of relay BS to battery C, and another stick circuit for this relay passes from terminal B through back contact 2li-2Gb of relay GHP, front contact 23 of relay BS, and the winding of relay BS to terminal C. The function of the stick circuit including back contact 22 of relay A5TR is to preventrelay BS `vfrom becoming deenergized during the interval of time which elapses between the opening of the pick-up circuit ior relay ES at front contact 2-2a of relay BHP and the closing of the 4other stick circuit for relay GS at back contact 2li-20h of relay SHP. A Y

The relay SS together with the track relays A.MTR and 5TH. control a time element relay TE over a circuit which passes from terminal B through front contact 26 of relay GS, Wire 21, the winding of relay TE, front contact 28 of relay ETR, back contact 29 of relay A5TR and front contact 3D oi relay BS to terminal C. It will be seen, therefore, that whenever a westbound train enters section A5T and deenergizes track relay A5TR, the resultant picking up of stick relay SS will complete the circuit for relay TE provided section 5T is then unoccupied, so that front contact 28 of track relay 5TH, is closed.

The time element relay TE may be of any suitable type such for example as that described and claimed in an application for Letters Patent of the United States, Serial blo-732,851 iiled by Branko Lazich and Harry E. Ashworth on June 28, 1934, for Electrical relays, now U. S. Letters Patent No. 2,172,888, granted Sept. l2. 1939, and is provided with a back contact 2li which is closed at all times when the relay is deenergized and which remains closed when the relay becomes en ergized until after the time interval for which the relay is set has expired, and with a time element contact which is open when therelay is deenergized and whichremains open after the relay becomes energized until after the expiration of the time interval for which the relay is set. The time interval for which the relay is set can readily be varied, and will be so adjusted that it will be greater than that required for a train to traverse section A5T if the average -speed of `the train exceeds a predetermined speed such for example as 30 miles per hour, whereby the relay TE will close its timing contact when and only when the speed of a train traversing section AST is less than said predetermined speed.

Relay 5H is provided with an energizing circuit which passes from terminal B through front contact 3l-3la of a repeater relay SHP, vfront contact 32 of track relay ASTR., iront contact 33 of track relay ETR, front contact 34 of track relay A5T'R, front contact 35 of track relay 5TH., the winding of relay 5H, common' wire 5C and back contact 3'1-3'11)` of a stick relay 9S to terminal C. Relay 5H is also provided with another energizing circuit which is similar to that just described except for the fact that this vlatter circuit includes a front contact 3'1--31 of relay 5S instead of back contact 31-31b of this relay, and a back contact 3I-3lb of relay SHP instead of front contact 3l-3la of this relay. These circuits are so arranged that when the circuit first traced is closed relay 5H will be supplied with current of normal polarity, whereas when the circuit last traced is closed relay 5H will then be supplied with current `or" reverse relative polarity. f

The control circuits for the relays BHP and 9S are not shown, but it will be readily understood that these circuits will be similar to those previously described for controlling relays GHP and 5S.

The relay 5H controls the relay 5HP over a circuit which will be vobvious from an inspection of the drawing in such manner that relay 5HP will be energized whenever relay 5H is energized. i i

Associated with signal 5 is an eastbound stick relay 5S which is controlled by the two track relays 4TH. and 5TR and the track repeater relay I 5I-IP in` such manner that relay 5S will pick up during the interval required for relay 5I-IP to drop when an eastbound train enters section 5T ,and deenergizes track relay 5TH, and will subsequently remain stuck up until the train clears section 6T. The pick-up circuit for relay 5S passes from terminal B through front `contact 5HP-20--2lla of relay SHP, back contact 5TR- 2l of relay ETR, back contact 4TH-92 of track relay llTR, and the winding of relay 5S to terminal C. One stick circuit for relay 5S passes from terminal B through back contact 2.2 of relay .5TR, front contact 23 of relay 5S and the winding of relay 5S to terminal C, while another stick circuit for relay 5S passes from terminal `B .20 through back contact SI-IP-Z-Zllb of relay 5HP, front contact 23 of relay 5S and the winding of relay 5S to terminal C. The function of the one stick circuit 'is to maintain relay 5S energized during the interval between the opening of ii025 front contact 5HP-2020a of relay SHP and the closing of the back contact 5HP--2-2b of relay I-lSP.

The home relay 5H also controls the distant relay SAD over a circuit which passes from ter- 30 minal B throughfro-nt contact 5H-40 of relay 5H, normal'polar contact 5H-4l of relay 5H and the windingyof .relay SAD to terminal C. It will be obvious lthat this circuit will be closed only when relay 5H is energized in its normal direction, and it follows that when relay 5H loecomes deenergized and causes the signal 5 to display a redor stop signal relay 3AD will also become dcenergized and will cause signal 3 to display a yellow or caution signal.

Associated with the signals 4a and 4b is a westbound stick relay 4S corresponding to the eastbound stick relays 5S associated with signal 5. The stick relay 4S is provided with two pick-up circuits one of which passes from terlt, minal B through front contact 4HP-Jl545a of relay 4BP, back contact 4TR-46 of track relay 4TR, `back contact 5TH-II of track relay 5TR and the winding ofrelay 4S toy terminal C, and the other of which passes from terminal B through front contact 4111-1-49 of relay 4biH, back .contact 4TH-46 of track relay llTR, back contact 5TR`|I of relay STR and the winding of relay 4S to terminal C.

Relay 68S is .also provided with two stick cir- 55 cuits, one of which passes from terminal B- through back contact 'HP--l-Mb of relay dHP, back contact IDH-t8 of relay MJH, front contact KR-Ell 'of relay KR, front contact 5l of relay 13S and the winding of relay 4S to ter-,150 minal C, and the other of which stick circuits passes from terminal B` through back contact flTR-l'l `of track relay ATR, front contact KRf-ll of relay KR, iront contact 5l of relay 4S and the winding of relay flS to terminal (1:65 The manner in which these pick-up and stick circuits control relay 1S will bc made clear as the description proceeds. y

The reference character 3bTPS designates a track repeater relay. This relay is providedrz() with a pick-up circuit which includes iront contact 52 of track relay 35TH, and with a stick circuit which includes a front contact 5 3 of track relay ATR and its own front contact 55.

The switch stick relay SWS is `provided with 7,5

teo

one pick-up'circuit which passes from terminal B through front Contact 25 of time element relay TE, front contact 93er relay GPS, and the winding of relay 3WS to terminal C. The relay-SWS is also provided with another pick-up circuit which passes from terminal B through front contact 82 of'a slow releasing sidingstick relay BUS,

front contact 93 of relay GPS, and the winding of relay SWS to terminal C. v

The siding stick relay SbS `is provided with a pick-up circuit which passes yfrom terminal B through iront contact 3bTPS-55 of relay bTPS, back Contact 3bTR-56 of relay 3bTR, contact HBP- 5l of relay 4HP and contact 1S-59 of relay 4S in multiple, contact 5HP-.58 of relay 5HP and contact S-S of relay 5S in multiple, and the winding of relay 3DS to terminal C. This relay is also provided with a stick circuit which passes from terminal B through back contact 9G oi relay SWS, front contact 9110i relay 3JS, andthe winding of relay SbS to terminal C.

Relay SWS is further provided with a stick circuit which passes from terminal B through front contact 62 of track relay 4TR, front contact El of relay SWS, and the Winding of relay `BWS to terminal C. f

Relay Sal-I is provided with an energizing circuit which passes from terminal B through contact 65 of a time release T, back contact 3bS-94 of relay 3DS, back contact 24 of time element relay TE, front contact 6G of track relay ATR, front contact ETR-61 of track relay 5TR, front contact 68 of relay KR, normal polar contact EQ-tga of polar relay KR, front contact 'ill of track relay SbTR, back contact SWS- TI of relay SWS, and the winding of relay Sal-I to terminal C. It will' be seen, therefore, that relay SaH will become energized when and only when time refao' lease T is in its normal position,` relay 3bS is deenergized, time element relay TE is deenergized, sections lbT, 4T and 5T are all unoccupied, and the Aswitch occupies its normal position and is locked in this position so that the KR relay is energized in its normal direction.

The time release T may be of any desired type, but as here shown it is a clockwork time release similar to that shown and described in Letters Patent of the United States No. 1,989,522, granted to William C. McWhirter on January 29, 1935, for Time governed circuit controlling mechanisms.

k'Since the time release T is similar to the time release shown in the said McWhirter patent, it is believed that for purposes of the present disclosure itis sufiicient to state that this release is provided, in addition to the contact 65, `which contact is a normally closed contact, with a normally open contact 83 to be referred to hereinafter, and that, when the release is set into operation the contact S5 immediately becomes opened, and the contact 8D remains opened until the expiration of a predetermined time interval. After the release has been operated to open the contact 65 and close the contact 80, the contact 65 will subsequently remainopened andthe contact 80 will remain closed until the time release is manually restored to its normal condition.

Relay 3D1-I is provided with an energizing circuit which passesfrom terminal B through normally closed contact 55 oi time release T, back contact SbS-Qt of relay 3bS, backcontact 24 of time element relay TE, front contact 66 of track relay lTR, back contact 5TR61 of trackrelay 5TR, iront contact S8 of relay KR., reverse polar contact (iS-69h of relay KR, front contact 3WS-'l2 of relay 3WS`, and the winding of relay l 3171-1 to terminal C. It willbe obvious, therefore, that relay 3b H will be energized when and only when time release T occupies its `normal position, relay 3DS is deenergized, time element relay TE is deenergized, track sections @TR and STR are both unoccupied, the switch is locked in its normal position, and the switch stick relay ySWS is energized.

Relay l1-IP is provided with an energizing circuitwhich passes from terminal B through normally closed contact 65 of the time release T, back contact 3DS- 94 of relay S-IJS, back contact 24 of time element relay TE, front contact tlo of track relay ATR, front contact 'I3 of track relay SIJTR, front contact 'I4 of relay KR, normal polar contact l5-'i511 oi relay KR, front contact 1H-16 of relay 4H, back contact BWS--'l of relay 3WS, and the Windinig of relay GHP to terminal C. [Itfollows that relay HP will be energized when and only when time release T occupies its normal condition, relay 3bS is deenergized, time `element relay TE is deenergized,

track relays 4TR, and SbTR are both energized indicating that the associated sections are unoccupied, relay KR is energized in its normal direction, home relay dH is energized, and the switch stick relay SWS is deenergized.

Relay llbH is provided with an energizing circuit which is similar to that just described for relay SHP with the exception that this latter cir- .cuit includes reverse polar contact l-'lllb of polar relay KR and front contact 3WS-l8 of relay SWS in placeof normal polar contact l-l'a of`relay KR, front contact 1H-1B of relay 4H, and back Contact SWS-'ll of relay SWS. It will be seen, therefore, that this relay will be energized when and only when time release T occupiesits normal condition, relay S is deenergized, time element relay TE is deenergized, track section 4T is unoccupied so that track relay 4TR is energized, track section EbTRis unoccupied, the switch occupies its reverse position so that relay KR is energized in its reverse direction, and the switch stick relay SWS is energized.

`The relay GPS is provided with a first pick-up circuit which' is. closed when and only when relays Bbl-I, dvbH, 4HP and Sal-I are all deenergized, and which passes from terminal B through back contact 3BR- 83 of relay SDH, back contact 34 of relay llbI-I, back contact 4BP-85 of relay 1I-IP, back contact SaI-I-- of relay 3mi-I, and the winding of relay GPS to terminal C. Relay GPS is also provided with another pick-up cir` cuit which includes the back normally open contact 80 of time release T and the winding ol relay GPS as will be obvious from an inspection of the drawing.

In explaining the operation of the system as a whole, I shall rst assume that all partsr are in their normal positions in which they are shown in the drawing and that a train desiring to enter the `siding Y enters section 9T.`

The entrance of the train into section 9T will deenergize track relay STR which latter relay, in turn, will cause the relay BHP to become deenergized and interrupt the circuit for relaySH.

Relay 5H will therefore become deenergized` and will deenergize relay BHP, thereby causing signal 5, which previously displayed a proceed indication, to now display a stop indication. The deits front contact 5I-I-40 the circuit for the distant relay SaD, and, will thus cause signal 3a to displayia'caution aspect. y K

When the train enters sections AST and 6T, respectively, track relays ASTR and GTR, will become deenergized, and will thus hold the circuit for relay H open, so that when the train passes out of section 9T, signal 5 will continue to display a stop aspect and signal 3a will continue to display a caution aspect.

When the train enters section AST it will reduce its speed to such a value that the time required for it to traverse this section will be greater than that required for time element relay TE to operate'its time contacts '24 and 25, and the train will keep its speed at or below this value during the entire time it is traversing section AST. y y l The entrance of the train into section A5T will of course deenergize track relay ABTR, which will cause signals 5 and 3a to continue to display caution and stop aspects, respectively, The deenergization of track relay A5TR will also interrupt atk its front contact I5 the circuit for relay 6H, and relay 6H will therefore become deenergized and will deenergize relay SHP, thereby `causing signal 6 to displaya stop aspect.

The deenergization of relay A5TR will further complete the pick-up circuit for stick relay BS during the interval required for relay BHP, which as was previously pointed out is a slow releasing relay, to open its front contact 2li- 2011, and, as soon as relay 5S picks up, its stick circuit ,inclucling back contact 22 of track relay ASTR will become closed, so that when front vcontact 20,- Zli-a of relay SHP finally opens, relay GS will remain energized. Thereleasing `of the armature of relay BHP will also complete the other stick circuit for relay SS, and itwill be apparent, therefore, that relay GS will remain energizedr even though the train now completely passes` out oi section AST and causes relay ASTE to again pick up, thus interrupting the one stick circuit for relay GS including the front contact 22 of track relay ASTR. y y

The picking up of relayGS completes at its front contacts 2 and Si()` the pick-up circuit for time element relay TE, and since the time required for the train to traverse section AST willbe longer than the pick-up time for relay TE, relay TE will pick up its armature while the train is traversing section AST, and will openitsback contact 24 and close its front contact`25.

The opening of back contact 24 of relayTE interrupts the circuits for relays Sal-I, Shi-I, 4I-IP and libH, thereby causing relaysSaI-I and lil-1P to become .deenergized, and hence insuring that signals 3a, 3b, 4a and 4b will now' all display stop aspects. l

The deenergization of relays SaI-I and 4HP also completes the pick-.up circuit forrelay GPS, and this relay therefore picks up its armature and closes its iront contacts VGPS- i, GPSi-Z and, 93. The closing of contacts GPS``I` and GPS-2, in turn, will complete the normal 'enerj vgizing circuitfor relay SWR, and this relay will therefore pickup its neutral armature, and thus causecurrent of normal polarity" to be supplied toswitch machine SM. The application of` cur,- rent to the'switch machine SM under ,thesel conYAY ditions, however, will have no effect on the switch since the switch already occupies its normal: position. a k

AThe closing of vfront contact v9S of vrelay GPS completes the previously traced` ypickfup circuit for relay SWS including front contact 25 of time element relayjvIE,` and relay SWS therefore picks up its armature and .closes its stick circuit including its front contact 6I and front contact 62 of` track relay ySTR.. The closing of the stick circuit for relaySWS insures that this relay will remain energized when the circuit for time element relay TE subsequently becomes opened at iront contact 2S of track relay STR due to the entrance of the trainin'to track section 5T.

As soon as `relay SWS becomes` energized, it reverses. the polarity, of the current supplied to relay SWR which causes the switch to move to its reverse position.V This movement of the switch, in turnrevers'e`s`the polarity of the current supplied to relay KR, and this Vrelay then reverses its polar armature, therebycausing relays SDH and libI-I to `pick up and hence causing signals 3b and ib to displayclear aspects. The picking upof relays SDH and dbH also interrupts the energizing circuit for relay GPS, which relay now becomes deenergized and deenergizes relay SWR, to thereby prevent lany further movement `of the switch under these conditions. ,v

It shouldv her'efbe noted that in order for relay SWR to become energized in its reverse direction and reverse the switch, it is necessary for relay GPS to be energized, and this relay will not be energized unless relays SbI-I, dbi-I, 4BP and Sal-I are all deenergized, thus insuring that the switch will only be reversed when all signals governing traffic over it occupy their stop positions. f

The4 train may,4 now enter section 4T. When thetrain does this, track relay 4TR. will of course become deenergized and will interrupt at its front Contact 66 the circuits `for relays SbH and MaI-I, which willV cause signals 3b and 4h to again display stopl aspects, and relay GPS to again become energized. The energization of relay GPS under these conditions, however, will not complete the circuit forrelay SWR since this circuit will then be open at front contacts I3 and i4 of track relay 4TR.-

TheY deenergization of track relay dTR will also maintain the circuit for `relay 6H open, so that this relay and relay; SHP will remain deenergized, thereby causing signal 6 to continue yto display a stop aspect. i

The deenergization of relay 4TR will further interrupt atits front contact 62the stick circuit 'forrelay SWS which will cause this relay to become deenergized.

When theutrain` Venterssection SUI', the resultant `(,ieer'i'ergifzation of track relay SbTR will cause the pick-upcircuit for relay SbTPS to become opened at front contact 52 of relay SbTR, and since the stick circuit for relay SbTPS will then be openiatfr'ont contact 53 of' relay 4'I Rrelay SDTPS willlbecome deenergize'd. The deenergizationofirelaySbTPS under these conditions, however, willhav no 'effect on 'the remainder of the apparatus.4

As soon `as the train passes outof section 4T, and causes relay llTl'A-t` to pickup, relay SWR will again befsuppliedwith current of normal polarity,which willl cause the switch to return to its normal positiorij,` Whentheswitch returns to its normal` position, relay KRwill lagain become energized in its normal direction.

i The pickingjup of relay 4TR will also complete the circuit for relay `lslgthereby causing this relai7 tcl, pick upand lcomplete,the pick-up circuit of relay .6I-IP. RelayHP will therefore also pick up and cause signalsto displaya clear aspect.

VWhen the train clears section 35T, the resulting picking up'of track relay 3bTR will cause relays 3bTPS, SaH and HP to pick up, whereupon signals 3a and 4a willidisplay clear aspects and signals 3b and `lb will display stop aspects. All parts will then be restored to the positions in which they are shown in the drawing.

I shall now assume that there are no trains appreaching the switch 3 in either direction on the main track X, and that an eastboound train in the siding Y Wishes to proceed. The train upon entering section SUT will deenergize track relayy BbTR, which will interrupt the circuits for relays 3aH and GHP, thereby causing signals 3a and 4a to display stop aspects.

The deenergizaton of track relay3bTR also completes, during the brief interval of time required for relay AHF to open its contact 4l-IP--51 after it becomes deenergized, the pick-up circuit for relay .3bS, whereupon this latter relay picks up and closes its stick circuit including back contact Slof relay 3WS.

The picking up of relay 3DS opens the circuits for all four signal control relays 3aH, 35H, ill-IP` and GUI-I, thereby insuring that these signals will continue to display stop aspects under these conditions.

As soon as relays 3aH and 4HP become deenergized, the pick-upcircuit for relay GPS becomes closed, and this relay therefore becomes energized and completes the pick-up circuit of relay `SWS including front contact 92 of relay 3DS.

The picking up of relay 3WS, in turn, completes at its front contact 6I its stick circuit, and interrupts at its back contact the stick circuit for relay 35S. Relay 3DS thereupon becomes deenergized and interruptsr the pick-up circuit which caused relay SWS to become energized. Relay SWS remains energized, however, by Virtue of its stick circuit.

yThe picking up of relay SWS also reverses the polarity of the current supplied to relay SWR, and this relay therefore reverses its polar armature, thereby causing the switch machine to move the switch 3 to its reverse position.y As soon as the switch reaches its reverse position, relay yKR becomes energized in its reverse direction and completes the circuits for relays 3bI-I and. bH. These relays therefore become energized and interrupt the circuit over which relay GPS was previously energized, aswell as complete the cir-` the signals 3b and 4b are now displaying their least restrictive indication, the train may now proceed.

When the train enters section 4T, track relay ATR becomes deenergized and interrupts at its front contact S5 the circuit for relay 6H. Relay 6H thereuponbecomes deenergized and deenergizes relay GHP, thereby causing signal 6 kto display a stop aspect,

` Thdeenergization of track relay 4TR also 1nterrupts at its front contact B6 the circuits for relays SDH and AUI-I, thereby causing signals3a and. 4b to display stop aspects and causing relay GPS to again become energized.

The deenergizaton Vof track relay 4TR further interrupts the stick circuit Vfor relay 3WS so that this relay now becomes deenergized. The deenergizaton of this relay, however, does not reverse the polarity of the current supplied to relay SWR because its circuit will then be open at front contacts' I3 and I4 of relay 4'IR.

The deenergizaton of relay TRsfurther interrupts the stick circuit for relay 3bTPS which now becomes deenergized.

When the train enters section 5T, the resultant deenergizaton of track relay ETR causes relay 5H, and hence relay SHP to become deenergized, therebycausing signal 5 which previously displayed a clear aspect to now display a stop aspect.

rIhe deenergizaton of relay ETR also maintains the circuit for relay GH open, interrupts at its front ycontact 6l the circuit for relay SUI-I, and completes at its back contact 2l the circuit for stick relay 5S. Relay 5S thereupon becomes energized and completes its stick circuit including back contact 22 of track relay 5TR to subsequentlyfmaintain it energized as long as the train remains in section 5T, The energization of relay 5S under these conditions has no immediate effect on the remainder of the apparatus, the function of the relay 5S being to permit following train moves in accordance with. standard absolute permissive block signaling practice.

When the train clears section 3brT, track relay SbTR will pick up and reestablish the pick-up circuit for relay SU'IPS, whereupon relay 3bTPS will again become energized.

When the train clears section 4T, the resultant reenergization of track relay GTR will cause it toclose its front contacts i3 and I4. When this happens, the circuits for relays 3aH`and 3bH will both be open'at contact STR- 6l of track relay 5TR, the circuit for relay 4HP Will be open at normal polar contact 'l5-15a of relay KR,

` and the circuit for relay IUI-I will be open at front contact 3WS`I8 of relay SWS, so that relays 3aI-I, SDH, lil-IP and dbi-I will allibe deenergized and relay GPS will be energized. Relay SWR will therefore now be supplied with current of reverse polarity and will cause the switch machine SM to become energizedy and restore the switch-3 to its normal position. As soon as the switch reaches its normal position, relay KR will become energized in its normal direction, and will'complete the circuit for relay 4I-IP, thereby causing-signal 4a to display a clear aspect.

From this point on the operation of the apparatus will be in accordance with standard practice in rabsolute permissive block signaling systems, and since such systems are well known, it is believed that this operation will be readily understood by those skilled in the art Without further detailed description.

I shall now assumev that an eastbound train which is waiting in the siding Y to the left of the fouling post FP rdesires to enter the main track X as soon as a westbound train which is approaching the switch from a point to the left of thesection 9T passes the switch.

Under these'conditions, the operation of the apparatus will be similar" to that previously described for a westbound train desiring to enter the siding Y until `the train passes signal 6. When this happens, if the train is not already traveling at a speed of more than 30 miles per hour, it will increase its speed, and will sub.-

sequently maintain its speed at a suiciently high value so that time element relay'TE will not pick up while the train is traversing section AST. VAs a result, relay SWS will remain deenergized and cause'fthe switch to be held in its normal position.

V When the train enters section 5T, the resultant deenergizaton of track relay STR will interrupt at its front contact 5TR-6'l the circuit for relay Sal-I, and this relay will therefore become deeneraspect.

gized and will cause signal 3al to display a' stop aspect.

The westbound train upon entering section 4T will deenergize track relay ATR, whereupon relay 4IIP will become deenergized and cause signal 4a todisplay a stop aspect. Thel relay AHF, in turn, will complete the circuit `for relay GPS which will then pick up, but the picking up of this relay will have no effect on the'rernainder of the apparatus sincesthe circuit for relay 3WR. will then be open at front contacts I3 and lil of track relay ATR.

The deenergization of also cause stick relay 4S to become energized since track relay 5TH. will then still be deeneru gized, and as a result relay 4S Will pick up and close both its stick circuit including back contact lll of track relay li-TR and its stick circuit includ-` ing back contact HP- 45 of relay 4H?.

When the westbound train enters section lT, track relay lTR will become deenergized and will interrupt the circuit for relay 4II,which latter relay, in turn, will become deenergized and will deenergize relay `AtPC. Relay AllPC upon becoming deenergized will reverse its pole changing contacts Il and i8, and as soon as the train clears section 4T to thus cause track relay 4TR to pick up, relay SI-I will pick up and will cause relay I-IP to pick up, thereby causing signal E to display a caution aspect.

The picking up of relay TR will also com` plete at its front contact 66 the circutfor relay Sal-I, whereupon this relay will pick up and will cause signal 3b to display a proceed at slow speed The circuit for relay HP, however, will now be open at contact 4H16 of relay 4H and relay tI-IP will therefore remain deenergized to retain the stick circuit for stick relay 4S closed.

The eastbound train which up until this time remained to the left of the fouling post FP may now proceed. As soon as the train enters section SUI', track relay 3bTR will become-deenergized. The deenergization of this relay will deenergize relay aH and will a stop aspect and relay GPS to become energized.

The deenergization of track relay SbTR will also complete the pick-up circuit for relay 3DS including contact IS-@59 of relay 4S, and relay 3DS will therefore pick up and complete its stick circuit.

When relay 3DS picks up, the pick-up circuit for relay SWS will become closed, and since relay GPS is then energized, relay SWR will be supplied with current of reverse polarity and will cause switch 3 to reverse. As soon as switch 3 reverses, polar relay KIRJ will reverse and will cause signals 3bl and filiy to clear. The reversal of relay KR. will also interrupt at its front contact KPV-5U both stick circuits for relay 4S, which relay will then `become deenergized. From this point on the operation of the apparatus will be identical with that previously described when an eastbound train which was in the siding traversed the stretch of track shown in the drawing.

When an eastbound train traverses the stretch of track X, the apparatus will function in a manner similar to standard practice in absolute permissive block signaling systems, and since this operation is in accordance with standard practice, it is believed to be unnecessary to describe it in detail herein.

It should be pointed out that one reason for including front contact 50 of relay KR in the stick circuit for relay 4S is to prevent relay 4S from being held up after it is picked up due to deenergization of track relay 4TH will` thus cause signal 3a to display a westbound train on the main track clearing section 4T if in the meanwhile aneastbound train on the siding entersvsection 36T, and thereby causes the switch to reverse. A i

Although I have herein shown and described onlyone form of railway traliic controlling apparatus embodying my invention, it is understood that various changes and modifications may be` made therein within the scope of the appended claims without departing from the spirit and scope of my invention. l

AHaving thus described my invention, what I claim is: J

.1. In combination, a stretch of railway track divided into sections including an approach sec-` tion, a siding connected by means of a switch with said stretch in rear of said approach section for trains approaching said switch in a facing point direction, a time element relay including a back contact which becomes opened and a` front contact which becomes closed when and only when said `relay remains energized for a predetermined time interval, signals for governing traflic over said switch controlled in part by trafllc conditions in the vicinity of said switch and in part by said back contact, means for energizing said time element relay while a train is traversing said approach section toward` said switch and means effective when the front contact of said time element relay is operated for` reversing said switch if said signals then occupy their stop positions. i

2. In combination, a stretch of railway track including a detector section having a switch located therein and an approach section, a time element relay having a back contact which be comes opened and a front contact which becomes closed after the relay has been energized for a predetermined time interval, means-for energizing said time element relay while a` train approaching said switch is traversing said approach section, signals `for governing tralc movements over said switch, means for clearingsaid signals to permit tranic to proceed over said switch if and only if said back contact is closed and said detector section is unoccupied, and means for reversing 'said switch when said front contact lie-1 comes closed provided said signals areV then` dis-i playing stop aspects.

3. In combination, a stretch of railway track including a detector section having a switch located therein and an approach section, a time element relay having a back contact which becomes opened and a front contact which becomes closed after the relay has been energized for a predetermined time interval, means for energizing said time element relay while a train` approaching said switch is traversing said approach section, automatic signals for governing traic over said switch controlled in part by said back contact, and means controlled by said front contact for reversing said switch. y,

4. In combination, a stretch of railway track including a detector section having a switch 1o-4 cated therein and an approach section, a time element relay having a back contact which becomes opened and a front contact which becomes closed after the relay has been energized for a predetermined time interval, means for energizing said time element relay while a train approaching said switch is traversing said approach section, automatic signals for governing traffic over said switch controlled in part by said back contact, a switch stick relay, means for energizing said stick relay when said front contact becomes closed and for subsequently maintaining it energized until a train enters said detector section, and means controlled by said switch stick relay for controlling the position of said switch.

5. In combination, a stretch of railway track including a detector section having ar switch 1ocated therein and an approach section, a time element relay having a back Contact which becomes opened and a front contact which becomes closed after the relay has been energized for a predetermined time interval, means for energizing said time element relay While a train approaching said switch is traversing said approach section, automatic signals for governing traiiic over said switch controlled iny part by said back contact, a switch stick relay, means for energizing said stick relay when said front contact becomes closed, a track relay for said detector section, a stick circuit for said stick relay including a front contact of said track relay, and means effective when said switch stick relay becomes energized for reversing said switch.

6. In combination, a stretch of railway track including a detector sectionhaving a switch lo-r cated therein and an approach section, a time element relay having a back contact which becomes opened and a time contact which becomes closed after the relay has been energized for a predetermined time interval, means for energizing said time element relay while a train approaching said switch is traversing said approach section, automatic signals for governing traiiic movements over said switch, means effective when said back contact becomes opened for causing said signals to display stop indications, and

means controlled by said time contact for reversing said switch if said detector section is unoccupied when said time contact becomes closed.

'7. In combination, a stretch of railway track including a detector section having a switch located therein and an approach section, a time element relay having a back contact which becomes opened and a front contact which becomes closed after the relay has been energized for a predetermined time interval, means for energizing said time element relay while a train approaching said switch is traversing said approach section, automatic signals for governing traine movements over said switch, means for causing said signals to display stop aspects when said back contact becomes opened, a safety relay, means for energizing said safety relay when said signals occupy their stop positions, a switch stick relay, a pick-Fup circuit for said switch stick relay including said front contact and a front contact' of said safety relay, a track relay for said detector section, a stick circuit for said switch stick relay ,including its own front contact and a front contact of said track relay, and means effective when said track and safety relays are both energized for moving said switch to its normal or reverse position according as said switch stick relay is then energized or deenergized.

8. YVIn combination, a stretch of railway track including a detector section having a switch located therein and an approach section, a time release including a normally closed contact which becomes opened immediately when said time release is set into operation anda time contact which becomes closed at the ,expiration of a measured time interval after said release is set` into operation, automatic signals for governing trailc movements over said switch, a time element 'relay including a back contact which becomes opened and a front contact `which becomes closed at the expiration of a predetermined time interval after said time element relay becomes energized, means for causing said signals to display stop aspects whenever said'normally closed contact or said yback contact becomes opened, means for energizing said time element relay while a train approaching said switch is traversing said approach section, a safety relay, a switch stick relay, means for energizing said switch stick relay when said safety relay becomes energized if said front contact is then closed and for subsequentlyfmaintaining said stick relay `energized until a train enters said detector section, meansfor energizing said safety relay when said signals are displaying stop aspects, and means for reversing said switch when said switch stick relay becomes energized if said safety relay is then energized and said detector section is unoccupied.

yMILLS R. SNYDER. 

